Entrance of Radioactive Phosphorus into Sphingomyelin of Various Tissues of Cat

Abstract

Conclusions

Radioactive phosphorus is incorporated into sphingomyelin to the greatest extent in the liver, the lung, and the intestinal mucosa. With the exception of the lung the tissues distribute themselves in approximately the same order for sphingomyelin activity as for total phospholipid activity. The lung is relatively higher in the case of sphingomyelin. Radioactivity in sphingomyelin reaches a maximum at about two days in most tissues. In the case of liver the total phospholipid fraction appears to be many times more active than sphingomyelin, indicating that this phospholipid, though possessing a certain definite activity, plays only a small part in phospholipid phosphorus metabolism in this organ.

The author is indebted to Miss Sylvia Levy for one-half of the radioactivity measurements and to Dr. William F. Bale and Dr. S. N. Van Voorhis for preparation of radioactive phosphorus.